1. Field
This application relates to vehicle diagnostic systems, including systems that diagnose motor vehicles, systems that include data recorders, and systems that process digital diagnostic data from a data stream.
2. Description of Related Art
Some vehicle diagnostic systems are configured with a connector that connects to a digital data port on the vehicle. Requests for different types of digital diagnostic data may be delivered through the port by the vehicle diagnostic system to the vehicle. Digital diagnostic data may then be sent in response through the port by the vehicle and back to the vehicle diagnostic system for analysis.
Some vehicle diagnostic systems include a data recorder. The user may enter a threshold value for a monitored signal that triggers the recordation of digital diagnostic data when the threshold is reached.
Unfortunately, systems of this type may fail to enable certain problems to be rapidly diagnosed. In some cases, this failure may be traceable to limitations in the ability of the system to access certain types of diagnostic information.
For example, a defective potentiometer may cause the acceleration of an engine in a vehicle to be choppy. The test requests that may be delivered through the vehicle's data port, however, may be insufficient to result in diagnostic information that readily illuminates this malfunction.
Analog test equipment, such as an oscilloscope, has also been used. This equipment may allow defects that are not readily detectable through a connection with the vehicle's data port to be studied. However, the defect may be erratic or may only appear for a very brief moment. These as well as other characteristics can make it difficult for even analog test equipment to capture the data that is clearly indicative of the defect. As a result, analog diagnostic equipment may also not readily illuminate a defect.